Hello,
I’m trying to load cuda driver api functions on runtime with dlsym, and i have encountered a strange error. I have this code that runs smoothly on my system ( compiled with nvcc etc ) :
#include <cuda.h>
#include <stdio.h>
int main(int argc,char *argv[]){
if(argc<3){
printf("Usage: ./test.cu <ptx_file> <cuda_device>\n");
exit(0);
}
// Error code
CUresult error;
// My number
unsigned int h_var=7;
// Initialize driver API
error = cuInit(0);
if((int)error!=0){
printf("Error! cuInit returned: %d\n",(int)error);
exit(0);
}
// Get Cuda Device and give handle
CUdevice cu_device;
error = cuDeviceGet(&cu_device,atoi(argv[2]));
if((int)error!=0){
printf("Error! cuDeviceGet returned: %d\n",(int)error);
exit(0);
}
// Create context to run on device
CUcontext cu_context;
error = cuCtxCreate(&cu_context, 0, cu_device);
if((int)error!=0){
printf("Error! cuCtxCreate returned: %d\n",(int)error);
exit(0);
}
// Load ptx code
CUmodule cu_module;
error = cuModuleLoad(&cu_module,argv[1]);
if((int)error!=0){
printf("Error! cuModuleLoad returned: %d\n",(int)error);
exit(0);
}
// Get kernel function
CUfunction func;
error = cuModuleGetFunction(&func,cu_module,"testing");
if((int)error!=0){
printf("Error! cuModuleGetFunction returned: %d\n",(int)error);
exit(0);
}
CUdeviceptr var;
// Allocate device memory
unsigned int size = sizeof(unsigned int);
error = cuMemAlloc(&var, size);
if((int)error!=0){
printf("Error! cuMemAlloc returned: %d\n",(int)error);
exit(0);
}
// Copy variable to host
error = cuMemcpyHtoD(var,&h_var,size);
if((int)error!=0){
printf("Error! cuMemcpyHtoD returned: %d\n",(int)error);
exit(0);
}
// Lauch kernel
void *args[] = {&var};
error = cuLaunchKernel(func, 1, 1, 1, 1, 1, 1, 0, NULL, args, NULL);
if((int)error!=0){
printf("Error! cuLaunchKernel returned: %d\n",(int)error);
exit(0);
}
// Get result to host
error = cuMemcpyDtoH(&h_var,var,size);
if((int)error!=0){
printf("Error! cuMemcpyDtoH returned: %d\n",(int)error);
exit(0);
}
// Free device memory
error = cuMemFree(var);
if((int)error!=0){
printf("Error! cuMemFree returned: %d\n",(int)error);
exit(0);
}
// Destroy context
error = cuCtxDestroy(cu_context);
if((int)error!=0){
printf("Error! cuCtxDestroy returned: %d\n",(int)error);
exit(0);
}
// Print result
printf("var: %d\n",h_var);
}
with a ptx code written by me: (it’s a simple addition, just to test that it works)
.version 1.4
.target sm_10, map_f64_to_f32
.entry testing (
.param .u64 mynum)
{
.reg .u64 %r;
.reg .u64 %i;
ld.param.u64 %r,[mynum];
ld.global.u64 %i,[%r];
add.u64 %i,%i,3;
st.global.u64 [%r+0],%i;
exit;
}
So far so good. Then i took the code and loaded every function with dlsym like this:
/* Lauch kernel */
void *args[] = {&var};
int (*_cuLaunchKernel)( void *, unsigned int, unsigned int, unsigned int, unsigned int, unsigned int, unsigned int, unsigned int, void *, void **, void ** );
*(void **)(&_cuLaunchKernel) = dlsym(dlhandle, "cuLaunchKernel");
(*_cuLaunchKernel)(cu_func,1 , 1, 1, 1, 1, 1, 0, NULL, args, NULL);
/* Get result to host */
int (*_cuMemcpyDtoH)( void *, void *, size_t );
*(void **)(&_cuMemcpyDtoH) = dlsym(dlhandle, "cuMemcpyHtoD");
error = (*_cuMemcpyDtoH)(&h_var,var,size);
( The rest of the code is in the same logic ). All of my functions return with 0, which means everything went ok, except the last one _cuMemcpyDtoH , which returns error 1 ( = cudaErrorMissingConfiguration ). Can someone explain what this error means, and why it occurs? Is there a way to solve it? And why it shows up when i load the functions on runtime?
Thanks.
My system:
nvcc release 4.1
GPU : GTX 480
NVRM version: NVIDIA UNIX x86_64 Kernel Module 285.05.32
GCC version: gcc version 4.5.2 (Ubuntu/Linaro 4.5.2-8ubuntu4)